Electrotherapeutic system and apparatus therefor



Feb. 7, 1933. PULLWlTT 1,896,647

ELECTROTHERAPEUTIC SYSTEM AND APPARATUS THEREFOR Filed Dec. 26, 1930 2 Sheets-Sheet 1 noun 1 Arroe/vks y Patented Feb. 7, 1933' tion, changes UNITED STATES PATENT OFFICE HERMAN P. PULLWITT, 01F. OAK PARK, ILLINOIS, ASSIGNOB 'IO'MCINTOSH ELECTRICAL CORPORATION, OF CHICAGO, ILLINOIS, A CORPORATION OF DELAWARE ELECTBOTHEBAPEUTIC SYSTEM AND APPARATUS THERE FOB Application filed December 26, 1880. Serial No. 504,814.

The invention relates to a therapeutical low tension current converting system, comprising novel means for changing the current characteristics of an alternating or direct current for the purpose of increasing the therapeutic effect of such a current.

In the treatment of impairednerve and muscle by means of an electric current it has been found that application of the negative pole of the treatment circuit. increases the irritability of the nerves and that application of the positive pole decreases the irritability of the nerves. It has also been found that it is not the time during which the current is ap lied to a nerve that produces the therapeutical effects, but that-these effects are produced by sudden reversals in the o larity of the applied current and abruptc osures and openings of the circuit supplying the current flow.

Alternating currents in which the polarity reverses several hundred times per second have been used, but the reversals of polarity of an alternating current, regardless of frequency, are --not sudden reversals but are gradual, due to correspondingly gradual potential changes ineither direction. current characteristics of alternating current render it undesirable for the treatment of impaired nerve and muscle, and it is the purpose of this invention to provide a current converting system which roduces a current which is free from these 0 jections.

One object of this invention is to produce a current in which the polarity reverses rapidly and suddenly and in which the current increases and decreases abru tly. Each of the current im ulses produced by this invenii'om one of its limitin values to the other, whether the impulses unidirectional or reversed in kind, without the accompanying voltage variations which are characteristic of the usual alternating current, thereby increasing the therapeutic value of the electric current delivered b my system, above anything-possible in'app ying the usual alternating current to a patient.

Another object of the invention is to profrequency of the reversals without changing ity and the abrupt closures and openm These v, duces the closure vide means for increasing and decreasing the the potential of the current. To accomplish this I provide a substantiall non-inductive current converter, which is riven by a variable speed motor. By this means it becomes possible to change-the frequency of the reversals for varying the therapeutic effect, without changing the voltage of the current.

Another object of the invention-is to provide rest periods between the current reversals, as it is not the length of time during which the current is applied to a nerve or muscle, which determines its therapeutic effeet, but it is the sudden change in the polar;

o the current flow that produce intense erapeutic efi'ects.

Another object of the invention is to roduce low tension current impulses in w ich duce the eifects which the polar properties of V the electric current have on the nerves; namely, the negative pole increases the' irritability of a nerve, whereas the positive pole decreases the irritability of a nerve. In order to reduce .the irritability which is produced by the negative pole, without raising the frequency to a point where artificial stimulation of nerve and muscle is impaired, I have found that by interposing rest periods between the current pulsations, the time during which the current is flowing can be reduced to a point where irritation is reduced to a minimum or abolished altogether. For instance, with the commercial 60-cycle alternating current, the current is in a negative or positive direction, as the case may be, for

1/120th of a second. In using my convert the time during which the current flows is then reduced by one-half or to l/QAOth of a second. Making the rest periods longer reperiods without changing the frequency of the reversals.

Another object of the invention is to produce interrupted currents, in which the interruptions are so rapid as to reduce the period of current flow to a value where irritation which is caused by the negative pole is eliminated. Such currents are of value when it is desired to retain the physiological eiiects which the positive and the negative poles have on the human body. For example, the positive pole is-physiologically sedative and the negative poie is physiologically stimulative.

(lhe currents which I have found to be very effective in the treatment of human ailments are as follows:

For impaired nerve and muscle, a current which reverses its direction about 680 times per second, with rest and closure periods of equal duration, producesthedesired results. With this type of current, the time during which the current is either in a positive or negative direction is only 1/1360 of a secon For treatment where the physiological effect of thecurrent is desirable, a continuous current which is; rapidly interrupted produces the desired resultswithout the irritation which is present when the current value remains constant during the treatment. These current interruptions must occur with extreme rapidity, or electrical shock is experienced bythe patient. Interruptions occurring from about 250 to 1,000 times per second appearito be most efiective.

The absence of skin irritation seems to be,

as far as I am able to ascertain at this time,-

due to the short duration of current flow which is accomplished by my invention.

The novel means and features which I believe to be cha.racteristic of this invention willbest befunderstood by reference to the following description taken in connection.

with the accompanying drawings, in which Fig"; 1 illustrates in developed view, one

form of current converter which I employ.

F ig. 2 illustrates diagrammatically a systeniof electrical connections which Iemploy item of electrical connections which for producing rapid current reversals,

Fig. 3 is'a'diagrammatical view of the currentirnpulses which are produced by the system of connections illustrated in Fig. 2,

Fig. a; illustrates diagrammaticall' a sys- I employ for producing a rapidly interrupted current.

'F1g..5 is a dis ammatical view of the current impulses w. ich are produced-by the system of connections illustrated in Fig. 4, Fig. 6 is a diagrammatical view of the current impulses which are produced. by t .e

system of connections illustrated ln'FIlg. 4 with wire 34 removed, and

Fig is a diagrammatical view or" illus-' trative means for driving the current con- .verter at variable speed.

necting the current converterto an input circuit. Brushes 8 and 9 are in contact with the segments and are used for connecting the current converter to a load or output circuit. The input and on ut circuit connections "may be interchanged, ut I prefer to connect the input circuit to brushes'6 and 7; The commutator described, as illustrated rin Fig- 7 may be mounted for rotation on the shaft of a variable speed motor M supplied with current from the terminals 12 and '13 below described, of a source of current S,:through wires 39 and 40 and variable-resistance 41, so that by changing the amount of the resistance 41. in circuit vwith the motor,-f anydesired speed of rotation of the commutator andfrequency of the current impulses'delivered from the commutator, maybe secured. It will be understood that the commutator may be similarly rotated and-the 's ame result secured, in any other desiredlmannen i- In Fig. 2, I s ow the circuit'jconnections of a system for producing arhighlyefi'ect-ive low tension therapeuticcurrent' in whicli the current converter shown in-Fig. 1," is usedfor converting a continuous current intoara'pidly reversing current in which restperiods are interposed between thereversal's: -To accom plish this by means of the usualalternating current supply, I use a transformer 10, having a magnetic core 14, primary winding 11 and secondary-winding 15. Primary wind ing terminals 12-and 13 are connected to an alternating current supply S5- The secondary 15 delivers an ungrounded current by means of wires 16 and-17 to a full wave rectifier 18'; any-or the well known full waverec'tifiers,

for example, acopper oxide-rectifier'of the? electronic dry contact type," may 'be used. Output wires 22 and 23 of rectifier 18 carry a unidirectional current. positive charge and wire 23 is negatively ch arged. Reectance coil 19 wound on a mag netic core 20 is inserted in the positive which is connected with brushh and in turn with ring 2. Wire 23 is connected with brush 7 and in turnwith'ring 31 Segments 24 and 25 thereby become negatively and positively charged respectively at a constant potential by means of the connecting pins :1

1 3. Brush 8, when it is in contact with a seg- Srmzlar numerals refer to similar parts throughout the several views,

ment 25 as shown, supplies a positive charge through wire2'i to'the output-terminal 29:

W ire 22 carries a grammatically shown in Fig. 3, as follows:

Since brush 6 is connected with the positive pole of rectifier 18, and brush 7 is connected with the negative pole of said rectifier, all segments 25, through their connecting pins 5, are positively charged, and all segments 24', through their connecting pins 5, are negatively charged. Brushes 8 and 9 are positioned to be in contact for each current impulse, with oppositely charged segments. With brushes 8 and 9 in contact as shown and described, a current impulse flows through the load 30 in a positive direction, as indicated at 31 in Fig. 3. Rotating the current converter in the direction of the arrow shown in Fig. 1, brings the next following segments 1 into contact with brushes 8 and 9 and as these segments are not connected with rings 2 and 3 and no current then .fiows through the load 30 in Fig. 2, a rest eriod indicated at 33 in Fig. 3, is produced.

otating the current converter still further, brings a negatively charged segment 24 into contact with brush 8 and a positively charged segment 25 into contact with brush 9, with the result that a current impulse then flows through load 30 in a negative direction, as indicated at 32. Rotating the current converter still further, brings another pair of segments 1 into contact with brushes 8 and 9, thereby producing another rest period 33. Further rotation of the current converter repeats the cycle of operation described.

The path of the current through the system of connections illustrated in Fig. 2, is as follows: The current supply S, is connected'with terminals 12 and 13 of transformer primary winding 11. The secondary current flows, when wire 16 is positive with respect to wire 17, through section A of the rectifier, wire 22, reactance coil 19, brush 6, ring 2, segment 25, brush 8, wire 27, terminal 29, load 30, terminal 28, wire 26, brush 9, segmerit 24, ring 3, brush 7 wire 23-, section B of rectifier, and through wire 17 back to the transformer. When wire 17 is positive with respect to wire 16, the current flows from wire 17 through section C of rectifier to wire 22 and thence through the path above traced to wire 23, and thence through section D of the rectifier and wire'16, back to the transformer.

The rectifying action of the rectifier prevents the passage of the current through the wires 22 and 23 diiferently than described.

Condenser 21 although connected between the output wires of the rectifier 18, ofiers a high resistance to the flow of direct current, but ofi'ers a low impedance to any current pulsations which may pass through reactance coil 19, thereby preventing undesired current pulsations from entering the current converter.

From the description of the path of the current it will be seen that the rings 2 and 3 of the current converter Fig. 1, are always at constant polarity when connected as in Fig.

2, but as the current converter is rotating when in use, the brushes 8 and 9 and their associated output connections will be charged, first in one direction, then remain at zero potential, then become charged in the opposite direction and then remain at zero potential v for a similar period, after which the cycle of operation described occurs repeatedly.

' In Fig. 4 I show the circuit connections of a system for producing a highly effective low potential therapeutic current in which the current convertershown in Fig. 1, is used for interrupting the flow of current in a circuit of constant polarity. To accomplish this by means of the usual alternating supply cur rent, I use devices of the kind above described, and connected as above described in connection with Fig. 2, excepting as follows: as shown in Fig. 4, the wire 23 extends from. the rectifier 18 and is connected with the terminal 28 instead of being connected with the brush 7; the brush 7 is connected by wire 34 with wire 22 and thus with brush 6; and the brush 9 is disconnected from the rest of the wiring of the system. As before, the wires 22 and 23 are always positively and negatively charged respectively, and in this case, the brushes 6 and 7 are always positively charged, and the terminal 28 is always negatively charged. In this way, all of the segments 24 and 25 are positively'charged, the segments 1 being neutral as before. While either of the brushes 8 and 9 may be used to intermittently supply positive charges to the terminal 29, show the brush 8 so connected, it being understood that whichever one of said brushes is so used, the other of said brushes may be in disconnected condition, as shown for the brush 9. p

As a result oi the circuit connections and paths of current flow. above described, when the connections oi Fig. 4 are employed, each time the brush 8 rests upon segment 25 or 24, a positive current impulse is communicated to the terminal 29, through the load 30 to terminal 28, and then through wire 23 to rectifier 18; rotation of the current converter to move the next segment, which is a neutral segment 1, into contact with the brush 8, interrupts the current flow and produces a rest period; further rotation of the current converter moves the next segment 24 or 25 into contact with the brush 8 and communipulses and rest which I have shown cates another ositive current impulse to the terminal 29, ollowed by alternate rest periods and positive current impulses as shown in Fig. 5, where the current impulses and rest periods are desi ated 35 and 36 respectively. Where, as ilustrated, the segments are all of the same width and equally spaced, and the rotation is uniform, the current imperiods will be of equal duration. d se ent proportions an arrangement may be ei nployed, and that the frequency of the current impulses delivered by any particular construction of current converter-or commutator is determined by its speed of rotation.

Current pulsations 37 and rest riods 38 as shown in Fig. 6, are produce with the s stem of connections shown in Fig. 4 when the wire 34 is removed. In this case, the current pulsations are only produced by contact of the segments 25 with the brush 8. When segments 1 and 24 contact with brush 8, no current then flows through brush 8,

and the periods of current flow are shorter than the rest periods, the effect being the same as providing the current converter with narrow charged segments and wider neutral segments.

If no alternating current is available, direct current supply may be applied directly to he input brushes 6 and 7 tor the connections shown in Fig. 1, or to the brush 6 and terminal 28 for the connections shown in Fig. The rest and closure periods" may be changed by changing the thickness of the segments, as for instance thin segments for current closures and thick segments for the rest periods, produce shorter durations of the current closures and longer periods of rest; or reversin the connections, that 1s, connecting the tick segments for current closures and the thin segments for rest periods, increases the durations of current closures and reduces-the length of time of the periods.

From the above, it will be observed that the devices employed to produce the current impulses and interruptions, and the circuit connections used to apply said impulses to a patient, may be of substantially constant impedance, since they may readily be sub stantially free from inductance and capacity,

as a result of which, for any selected potential impressed upon the impulse producing devices, the effective potential of the current impulses produced may be maintained practically constant for difierent frequencies of said impulses produced by the frequenclng changing devices.

While the arrangements of the system and described, illustrate the invention in detail, it will be understood that modifications may be made in the parapparatus used and the circuit articular It will be understood that any desiredrangement employed without departing from the scope of my invention.

What I claim is:

1. In a system of the class described, the combination of alternating current rectifying means having alternating current supply terminals and unidirectional current delivery terminals, first circuit connections extending from said delivery terminals, pulsation suppressing means in said circuit connections, high frequency circuit changing contacts connected with said first circuit connections, and output circuit connections extending from said contacts, whereby rapid current impulses are abruptly and repeatedly communicated to said output circuit connections.

2. In a system of the class described, the combination of alternating current rectifying means delivering unidirectional current, pulsation suppressing means, delivery circuit connections extending from said rectifying means and connected with said pulsation suppressing means, circuit closing and opening mechanism in'said circuit connectons, and devices operating said circuit closing and opening mechanism at a desired frequency.

3. In a system of the class described, the

combination of alternating current rectifying means delivering unidirectional current, pulsation suppressing means, delivery circuit connections extending from said rectifying means and connected with said pu1sation suppressing means, circuit closing and opening mechanism in said circuit connections, devices operating said circuit closing and opening mechanism at a desired frequency, and speed changing mechanism controlling said operating devices.

4. Ina system of the classdescribed, the combination of alternating current rectifying means delivering unidirectional current, pulsation suppressing means, connections extending from said rectifying means and connected with said pulsation suppressing means, circuit closing and opening mechanism in said circuit connections, and devices operating said circuit closing and opening mechanism at a desired frequency, said circuit closing and opening mechanism comprising cooperating electric contacts having an open circuit relation for an appreciable part of each-cycle of their operation.

5. In a system of the class described, the combination of alternating current rectifying means delivering unidlrectional current, pulsation suppressing means, delivery circuit connections extending from said rectifying means and connected with said pulsation suppressing means, circuit closing and opening mechanism in said circuit connec tions, and devices operating said circuit closing and opening mechanism at a desired fredelivery circuit quency, said circuit closing and opening mechanism comprising cooperating electric contacts having an open circuit relation for a lon or time interval than the time interval of their closed circuit relation for each cycle of their operation.

6. Ina system of the class described, the combination of an inductive current converting unit, an electronic current converting unit, a mechanical current converting unit, circuit connections between saidunits, .and a source of supply currentfor said inductive converting unit, said mechanical current converting unit comprising a source of current impulses of constant potential and desired sign for delivery to a patients circuit. 7. In a current converting system, the combination of an. inductive, an electronic and I a mechanical current converting unit, each unit having input and output circuit connections, a source of alternating current connected to the input connections of the inductive converting unit, said output and said input connections of said inductive and said electronic units respectively being connected said output and said input connections 0% said electronic and said mechanical units respectively being connected and supplying 3o unidirectional current to said mechanical converting unit.

In witness whereof, I hereunto subscribe rlngoname this 15th day of December, A41)- I HERMAN P. PULLWITT. 

